diff --git a/server/helpers/custom-validators/users.ts b/server/helpers/custom-validators/users.ts
index 105c36600..b04970108 100644
--- a/server/helpers/custom-validators/users.ts
+++ b/server/helpers/custom-validators/users.ts
@@ -90,7 +90,7 @@ function isUserBlockedReasonValid (value: any) {
 }
 
 function isUserRoleValid (value: any) {
-  return exists(value) && validator.isInt('' + value) && UserRole[value] !== undefined
+  return exists(value) && validator.isInt('' + value) && [ UserRole.ADMINISTRATOR, UserRole.MODERATOR, UserRole.USER ].includes(value)
 }
 
 // ---------------------------------------------------------------------------
diff --git a/shared/models/http/http-error-codes.ts b/shared/models/http/http-error-codes.ts
index b2fbdfc5a..5ebff1cb5 100644
--- a/shared/models/http/http-error-codes.ts
+++ b/shared/models/http/http-error-codes.ts
@@ -4,7 +4,7 @@
  *
  * WebDAV and other codes useless with regards to PeerTube are not listed.
  */
-export enum HttpStatusCode {
+export const enum HttpStatusCode {
 
   /**
    * Official Documentation @ https://tools.ietf.org/html/rfc7231#section-6.2.1
diff --git a/shared/models/http/http-methods.ts b/shared/models/http/http-methods.ts
index 1cfa458b9..3f4adafe2 100644
--- a/shared/models/http/http-methods.ts
+++ b/shared/models/http/http-methods.ts
@@ -1,5 +1,5 @@
 /** HTTP request method to indicate the desired action to be performed for a given resource. */
-export enum HttpMethod {
+export const enum HttpMethod {
   /** The CONNECT method establishes a tunnel to the server identified by the target resource. */
   CONNECT = 'CONNECT',
   /** The DELETE method deletes the specified resource. */
diff --git a/shared/models/plugins/plugin.type.ts b/shared/models/plugins/plugin.type.ts
index b6766821a..016219ceb 100644
--- a/shared/models/plugins/plugin.type.ts
+++ b/shared/models/plugins/plugin.type.ts
@@ -1,4 +1,4 @@
-export enum PluginType {
+export const enum PluginType {
   PLUGIN = 1,
   THEME = 2
 }
diff --git a/shared/models/users/user-role.ts b/shared/models/users/user-role.ts
index 94413abca..687a2aa0d 100644
--- a/shared/models/users/user-role.ts
+++ b/shared/models/users/user-role.ts
@@ -1,5 +1,5 @@
 // Keep the order
-export enum UserRole {
+export const enum UserRole {
   ADMINISTRATOR = 0,
   MODERATOR = 1,
   USER = 2